public class Example3_6 {
    public static void main(String args[]){
      double sum=0,item=1;
      int i=1,n=20;
      while (i<=n) {
        sum=sum+item;
        i=i+1;
        item=item*(1.0/i);
      }
      System.out.println("sum="+sum);
    }
}

